The overall objective is to provide information on the type and probability of normal tissue damage from intraoperative irradiation as compared to more conventional irradiation protocols. The interest in intraoperative therapy was stimulated because of difficulty in delivering adequate radiation doses to tumors located near critical radiosensitive organs or tissues. Tumors adjacent to or including major blood vessels are difficult to excise completely. The aim of this study is to determine early and late response of canine paraaortic tissues to large single doses of radiation alone and following fractionated external beam irradiation. Sequential examinations will include arteriograms, intravenous urography, blood and urine chemistries, observations for peripheral nerve injury and electrophysiologic measurements. Necropsies at 2 and 5 years will provide tissues for morphometric analysis of peripheral nerves, muscles, great vessels and other paraaortic structure. Of particular interest will be the percentage volume changes in perenchyma, stroma and microvasculature. The histologic analyses will be compared to the sequential functional studies. The isoeffective doses will be compared for parameters for each type of dose delivery to determine the various relative effectiveness of large single radiation doses delivered intraoperatively alone or combined with fractionated radiation with the dose delivered by fractionated radiation alone. Those determinations have not been done but are essential to those developing human clinical trials to aid in judging the relative risk and potential benefit to patients with nonresectable or locally advanced cancer.